used compressor woes

[FunkyfullWidth]

Stumbled upon a decent deal on a compressor at a local antique shop. It's an 80 gallon 2 stage AMP. I found a few posts on the web about it but with no real info. Best I can gather is that it's a saylor beall 705 clone. Intercooler and aftercooler. 200 psi tank. Tag says it's cut offs are 145-175. Stamping on the tank puts it as a 1994.


When I initially looked at it the tag said 500 bucks. I snagged it for 450. The guy had a forklift to help load. Unloading was a tad trickier. My motor puller got it done, but it was hairy. First things first after getting it off the truck was a good once over. I took off the after cooler, belt guard and charge air tube to get a better spot to pick it from. I cleaned it all up and reasealed the pipe threads. I checked the oil, cleaned the air filter out, pulled the drain and the big plug off the front. OH BOY. FILLED with rust. And this is after I scraped and vacuumed it out for a while. There was almost 3 inches of scale built up. The drain was clogged, the safety releif under the gauge was clogged. ugh. Nightmare.



This thing must NEVER have been drained. The plus side. Compressor sounds good. I let it build to about 40 psi to check all the connections and safety valves for functioning. Unloader valve leaked and I'm thinking stuck check valve. The guy claimed that the motor was newer. So either way I'm ahead of the game I feel. I got a nice schrader bellows regulator and a parker filter with it.

My plans. I'm gonna wire it up and enclose it under my stairs. Eventually I plan on getting a new tank for it. I'm gonna go horizontal. I priced out tanks and new you can get them for about 500-600 bucks. But probably more. The oil company I work part time for has sonic testers for oil tanks. I'd like to try it out on this tank.

Moral of the story. When buying a used compressor, bring along the biggest pipe wrench you can and peek inside the tank. Because if your like me, jumping into **** and having zero good luck your gonna get bit.

 

[The Engine Room]

Once, I was called to repair a compressor at a feed mill that they said was short-cycling. I drained probably 70 gallons of water from the 80 gallon tank. The operator said he capped off the valve a few months ago "because it was leaking water and making a mess".

 

[G_P]

You can probably find a tank on Craigslist. Find someone selling a compressor with a broken pump or motor.

 

[Cyberbear]

Not wanting to be negative, but with all the items mentioned and money invested, you may have opened an expensive can of worms and will end up spending more than is reasonable, unless you have a desire to try and save this unit for personal reasons.

 

[CNGsaves]

OP . . . since you have access to ultrasonic testing of pressure vessel, I'd say go for it and let us know what you find out. Can you get that testing for free or very low cost ??

You could also do hydro test with water in tank once you get all that crud flushed out of there . . . ie the grease gun method.

This would be good "test case" of what to do when checking out older compressor that had poor drain maintenance. Please keep fellow GJer's updated with this thread. Good luck.

 

[FunkyfullWidth]

Ya, it's going to be way more then what I paid, but.. In the end I look at it like this. It's a newer leason motor, with a pump that's rebuildable for around 200 in parts. That's the majority of an air compressor right there. New motors and pumps are close to 400 a piece. And it came with about 100 worth of regulators and filters. Besides the tank and one check valve there's nothing I need to replace, just want. I'd rather start fresh.

I priced out a new check valve, gauge, safety reliefs, nylon unloader line, and braided charge air hose for less then 100 bucks. An compressor this big, 2 stage with bells and whistles, you won't find for what I'll have into it even with the new tank. Lately even the used ones (if you find one that isn't 3ph) are 1000 or more. I've been looking around a long time for decent compressor deals and there's alot of junk out there.

I have been looking around on craigslist for a deal with a junk motor or pump but good tank. I just get nervous about getting the same "deal" as I just did with this one.

 

[MoonRise]

My plans. I'm gonna wire it up and enclose it under my stairs. Eventually I plan on getting a new tank for it.

No.

Let's make that HELL NO!!!!!

The tank is no f'n good.

Remove it from any use as a pressure vessel.

That tank is no longer 'valid' as a pressure vessel.

Turn it into yard art or a BBQ/smoker/grill. Or scrap it.

And for any future event, NEVER use compressed air to 'pressure test' a suspect pressure vessel.

The amount of energy stored in a compressed gas (such as air) is a LOT (technical term there).

Pressure vessels are -supposed- to not fail suddenly or in a catastrophic manner. But sometimes they do.

And when they do, the aftermath can be, well, catastrophic.

Search the web if you want to.

One example is right here at

http://weldingweb.com/showthread.php?48232-Stay-from-those-old-compressor

A 'small' compressor tank let go suddenly. Broke the guy's hand in multiple places, broke his tibia, broke his femur. (femurs don't break too easily, they are the biggest strongest bone in the body!!!)

That tank needs to be tagged-out as a pressure vessel. Now.

think of it this way: The amount of energy stored in the compressed air in a tank can be roughly estimated like this.

Let's say that the motor is 'just' a 3 hp motor (3 'real' hp). That's 3 x 550 ft-lb/sec. Run the motor for only one minute and it has done 99,000 ft-lb of work. Let's throw in an electro-mechanical efficiency factor of 80%, and the motor has still done 79,200 ft-lb of work.

That's the same amount of potential energy (remember that work=energy) as lifting 79,200 lbs up just one foot into the air.

And dropping it.

On your foot, or your head, or any other body part you have.

And that's just if a 3 hp 80% efficient motor ran for just one minute.

Oh, but you say that the compressor pump is there too, and it is also not 100% efficient? True.

So we'll put in an efficiency factor of 80% for the compressor pump as well.

0.80 x 79,200 ft-lb = 63,360 ft-lb of work/energy

Running the motor and pump for just one minute has stored 63,360 ft-lb of work/energy in the compressed air.

Drop 63,360 lbs of weight from one foot up onto any body part(s) you choose. The result is going to pretty much be obliterated body part(s).

And THAT is a rough estimate of how much work/energy is in some compressed air if a 3 hp motor ran for just one minute.

If a rust-compromised pressure vessel lets go suddenly, all that work/energy can be released in an INSTANT.

That tank is NOT safe.

Do NOT use it as a pressure vessel.

IMNSHO.

 

[dbabicky]

And the race is on and here comes ............................................................... HA HA

 

[Streetbu]

Many years ago my Dad found a beer keg that floated in on the lake. He decided to see how much air it would hold for a portable air tank. Blew then end of it right off around 100psi. We weren't standing around it thank god but the end came crashing down on his Corvette. I don't know what he was thinking.... Seeing how much rust is inside that tank, I wouldn't use it. Just not worth the possibility of it failing and hurting me, let alone someone else....

 

[GYPSY400]

I would invest in a new tank before putting it into service.


Sent from my iPhone using Tapatalk

 

[sberry]

There are millions of these in service that look just like this. Most of them do, just no one ever looks in.

 

[cabin fever]

wow, after seeing this, I am going to go look at mine. I've never looked in the tank, but I drain it often, usually don't get much water out of it.

 

[goforride57]

$450? I bet they couldn't load it fast enough with a forklift.

 

[FunkyfullWidth]

450 was a deal from what i've been seeing around here. Most compressors this size have a 3 phase motor and they're asking 1000 bucks. I've been looking for years and this was the best deal that came up.

I still don't think I got a terrible deal, a bullet proof pump and a newer motor. Right there it's paid for. And Sberry you're right. There's probably way more compressors out there that are worse then this one. It was tough to tell, the outside looked rust free just dirty.

 

[brownbagg]

i have found many tanks free. I got three in my shop and two more at work. usually when the pump goes people throw the whole deal away, I bet the local scrap yard have hundreds

 

[FunkyfullWidth]

At my part time gig we got a 1951 gilbarco. Thing is pretty cool. It has a nice quiet chug to it, but takes about 20 minutes to go from zero to full. Since i've been using it I drain it after every use. I am curious about the inside though.

 

[BigNuge]

3" of scale is a lot. I agree that most compressor tanks are scaled/rusty inside, but 3" of scale is well above average. All that scale is material from the tank flaking off (more scale/more material missing from the tank). UT test it for sure.

Compresor accidents are not good for sure. If you do hydro-test the tank I'd suggest doing it with water and a hand pump. Water does not compress, so if the tank fails during the test it will just pop and piss everywhere....you'll need to change your BVD's after, but at least the tank won't hurt you!

 

[FunkyfullWidth]

So this compressor gets worse. I pulled the pump apart to see what I needed for parts. I started with the valves. Just a few caps and 5 valve covers.



I had to get creative to get the valve covers off. I found a bolt that had an 1 11/16" head. I cut the threads off and smoothed the top off.



I needed a way to transfer the hole spacing to the bolt head, I shadowed a piece of paper over the valve cover and the cut the pattern out and taped it to the bolt head. I then put it in the drill press and used a starter bit then hogged the holes out to 5/16 and tapped them 3/8.







Then I grabbed some shouldered grade 8 3/8 bolts and cut the head off, chucked em up in the lathe and ground em down to fit good into the holes on the covers.

Perfect fit! I had to make a few sets. Those things were in there tight. Hit em with the impact. But this is what I found.



All the valves had crud packed into them. I pulled everything else apart and found pits in a very worn out low side cylinder wall. You can see the ring at the top. Hoping to maybe find a source for a sleeve for it.




And the high side


Unloader filled with crud.


All in all, It's pretty trashed. I don't even really want to talk about it... But now moving forward and rebuilding it. I called a few places and can get rebuild kits for this pump, new valves, gaskets, piston rings and rod bearing inserts. The issue being the cylinder now. I'm going to check into hogging it out and sleeving it. The other option I considered was look into new jugs but for an actual saylor beall. I'm not sure how far off the bolt patterns are, but if metric to standard is all that's wrong I see no problem.

 

[redmondjp]

Thanks for laying it all out there - you spin the wheel and you take your chances. I do it myself all the time, and sometimes you end up with a very expensive boat anchor or doorstop!

Next step is to price out parts and machining costs to see what you're looking at. One thing is for sure - that is a unit that is worth rebuilding if you can still get the parts for it (which can't be said about a lot of the newer stuff). Only you can decide if the cost and time is worth it. For me, often it isn't, but I justify it as my hobby so I don't care. No different than somebody buying a lift ticket or a round of golf - if that makes you happy, do it.

My spin-and-lost story: I bought a non-running Onan generator a few years ago for $300; bought about $100 worth of parts for it (stupid, as it still wasn't running). Finally got it running, and it had a bad rod knock on one side. Ended up giving it away to a friend and he used it for parts. At least my friend got some value out of it.

 

[DekeT]

No.

Let's make that HELL NO!!!!!

The tank is no f'n good.

Remove it from any use as a pressure vessel.

That tank is no longer 'valid' as a pressure vessel.

Turn it into yard art or a BBQ/smoker/grill. Or scrap it.

And for any future event, NEVER use compressed air to 'pressure test' a suspect pressure vessel.

The amount of energy stored in a compressed gas (such as air) is a LOT (technical term there).

Pressure vessels are -supposed- to not fail suddenly or in a catastrophic manner. But sometimes they do.

And when they do, the aftermath can be, well, catastrophic.

Search the web if you want to.

One example is right here at

http://weldingweb.com/showthread.php?48232-Stay-from-those-old-compressor

A 'small' compressor tank let go suddenly. Broke the guy's hand in multiple places, broke his tibia, broke his femur. (femurs don't break too easily, they are the biggest strongest bone in the body!!!)

That tank needs to be tagged-out as a pressure vessel. Now.

think of it this way: The amount of energy stored in the compressed air in a tank can be roughly estimated like this.

Let's say that the motor is 'just' a 3 hp motor (3 'real' hp). That's 3 x 550 ft-lb/sec. Run the motor for only one minute and it has done 99,000 ft-lb of work. Let's throw in an electro-mechanical efficiency factor of 80%, and the motor has still done 79,200 ft-lb of work.

That's the same amount of potential energy (remember that work=energy) as lifting 79,200 lbs up just one foot into the air.

And dropping it.

On your foot, or your head, or any other body part you have.

And that's just if a 3 hp 80% efficient motor ran for just one minute.

Oh, but you say that the compressor pump is there too, and it is also not 100% efficient? True.

So we'll put in an efficiency factor of 80% for the compressor pump as well.

0.80 x 79,200 ft-lb = 63,360 ft-lb of work/energy

Running the motor and pump for just one minute has stored 63,360 ft-lb of work/energy in the compressed air.

Drop 63,360 lbs of weight from one foot up onto any body part(s) you choose. The result is going to pretty much be obliterated body part(s).

And THAT is a rough estimate of how much work/energy is in some compressed air if a 3 hp motor ran for just one minute.

If a rust-compromised pressure vessel lets go suddenly, all that work/energy can be released in an INSTANT.

That tank is NOT safe.

Do NOT use it as a pressure vessel.

IMNSHO.

Truly excellent number crunching on the potential perils of compressed air.

 

[Heavymetalmechanic]

Can you get away with just doing a heavy hone and oversized piston rings?

 

[MacMcMacmac]

Once, I was called to repair a compressor at a feed mill that they said was short-cycling. I drained probably 70 gallons of water from the 80 gallon tank. The operator said he capped off the valve a few months ago "because it was leaking water and making a mess".

I did the same thing with a 1500gal tank where the autodrain had been plugged with teflon tape from the day it was installed. It was like a fire hose going out into the parking lot.

 

[MacMcMacmac]

So this compressor gets worse. I pulled the pump apart to see what I needed for parts. I started with the valves. Just a few caps and 5 valve covers.



I had to get creative to get the valve covers off. I found a bolt that had an 1 11/16" head. I cut the threads off and smoothed the top off.



I needed a way to transfer the hole spacing to the bolt head, I shadowed a piece of paper over the valve cover and the cut the pattern out and taped it to the bolt head. I then put it in the drill press and used a starter bit then hogged the holes out to 5/16 and tapped them 3/8.







Then I grabbed some shouldered grade 8 3/8 bolts and cut the head off, chucked em up in the lathe and ground em down to fit good into the holes on the covers.

Perfect fit! I had to make a few sets. Those things were in there tight. Hit em with the impact. But this is what I found.



All the valves had crud packed into them. I pulled everything else apart and found pits in a very worn out low side cylinder wall. You can see the ring at the top. Hoping to maybe find a source for a sleeve for it.




And the high side


Unloader filled with crud.


All in all, It's pretty trashed. I don't even really want to talk about it... But now moving forward and rebuilding it. I called a few places and can get rebuild kits for this pump, new valves, gaskets, piston rings and rod bearing inserts. The issue being the cylinder now. I'm going to check into hogging it out and sleeving it. The other option I considered was look into new jugs but for an actual saylor beall. I'm not sure how far off the bolt patterns are, but if metric to standard is all that's wrong I see no problem.

Make sure you pull the block and give the small ends and crank a good looking over before you start buying parts for the top end. These pumps are known for soft cranks and weak small ends, especially in the HP pistons.

This should give some people a good idea of what those Eaton pumps are like, without all the hype from the dealer. Unless Eaton has spec'ed the pumps higher, these are the same thing. I know they claim to have steel rods in the Eatons, so maybe they asked for some upgrades to the design before they put the name on them.

Looks like asbestos gaskets too.

 

[txturbo]

I would invest in a new tank before putting it into service.


Sent from my iPhone using Tapatalk

There is a guy at the local swap meet sells brand new 80 gallon tanks for $35. He owns a water well company. Buys new compressors and cuts the mount off the top and keeps the whole assembly for water wells. The tanks are still bolted to the shipping pallet.